Injection device with dose metering mechanism with multiple anti-rotation locking system

ABSTRACT

A drive and dosing module for an injection device, and an injection device including the module, wherein the module includes a dosing member which can be displaced into one of several dosing positions in relation to a drive member to set a product dose, wherein one of the dosing or drive members forms several dosing stops at axially different heights and rotational stops that are associated with the dosing stops and the other member forms at least one selection element, and wherein the drive member can be moved in relation to the dosing member until it reaches a trigger position in which the at least one selection element attains one of the dosing stops and, in said trigger position, the selection element and the rotational stops combine to lock the rotation of the dosing member in both directions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Patent ApplicationNo. PCT/CH2005/00217, filed on Apr. 19, 2005, which claims priority toGerman Application No. 20 2004 006 611.4, filed on Apr. 23, 2004, thecontents of both of which are hereby incorporated in their entirety byreference herein.

BACKGROUND

The invention relates to devices for delivering, administering,injection, dispensing or infusing substances, and to methods of makingand using such devices. More particularly, it relates to a dose meteringmechanism with a multiple anti-rotation locking system and a device foradministering an injectable product, which enable a dose to be freelyselected by a user of the device. The injection device is particularlysuitable for applications where the user self-administers the productand is able to select, i.e. set or choose, the dose individually withevery administration. In some preferred embodiments, the device is aninjection device of the type used for administering insulin as adiabetic treatment, or for administering growth hormone.

Patent specification EP 0 713 403 A1 discloses a syringe foradministering liquid pharmaceutical mixtures and generally also otherliquids, which allows a dose of liquid to be administered per injectionto be set once. Specifically, a setting is made by a pharmacist.However, in the case of a patient who then has to self-administer thepharmaceutical liquid with the syringe, it is difficult to change thedose, once it has been set. The intention is to prevent an incorrectdose from being administered with the syringe. A syringe of this type isnot entirely satisfactory for all uses because in some treatmentregimes, an optimum dose varies depending, for example, on the time ofday, sporting activities or the consumption of meals.

Injection devices which satisfy the need for variable doses or dosingare known from patent specifications WO 97/36625 and DE 199 00 792 C2,for example. These two specifications relate to injection devices, eachof which has a conveying mechanism for dispensing the product, and adose metering mechanism for setting the product dose which can beconveyed and hence dispensed by the conveying device during a subsequentinjection. The conveying mechanism comprises a plunger, the forwardstroke of which conveys the product from a product reservoir, a plungerrod and a drive member for the plunger rod. The drive member and theplunger rod engage with one another so that a forward movement of thedrive member causes the plunger rod to move in the same way but thedrive member performs a reverse movement in the opposite direction untilit reaches a trigger position, from which another injection can beinitiated. The trigger position is determined by means of the dosemetering mechanism, which forms an adjustable dose setting stop for thedrive member. Although the known devices have proved to be efficient inpractice, they could still be improved to make them more reliable interms of ruling out the risk of incorrect doses.

Patent specification EP 0 879 610 B1 discloses a re-usable dispensingmechanism for medicaments. A projection mounted on the housing of thedevice engages in one of several grooves adapted to the projection,disposed on a selection element. The projection is resiliently attachedto the housing so that when the housing is turned towards the selectionelement, the selection element springs out of one groove into anadjacent groove, thereby making an audible clicking sound.

SUMMARY

One objective of the present invention is to provide a drive and dosemetering module and an injection device for administering an injectableproduct, which enable a dose to be freely selected while reducing therisk of incorrect dosage.

In one embodiment, the present invention comprises a drive and dosingmodule for an injection device, and an injection device comprising themodule, wherein the module includes a dosing member which can bedisplaced into one of several dosing positions in relation to a drivemember to set a product dose, wherein one of the dosing or drive membersforms several dosing stops at axially different heights and rotationalstops that are associated with the dosing stops and the other memberforms at least one selection element, and wherein the drive member canbe moved in relation to the dosing member until it reaches a triggerposition in which the at least one selection element attains one of thedosing stops and, in said trigger position, the selection element andthe rotational stops combine to lock the rotation of the dosing memberin both directions.

In one embodiment, the present invention relates to an injection devicefor administering an injectable product, wherein the device is portableand can be carried in a pocket, e.g., the type of device known as aninjection pen. The injection device comprises a housing with a reservoirfor the product, a conveying mechanism for conveying the product and adose metering mechanism enabling a product dose to be freely selectedfor every injection. The housing itself may constitute the reservoir.However, the housing may be designed as a housing compartment for aproduct container which may be of the type sold as standard in the formof a pre-filled ampoule. The expression “housing with a reservoir”should also generally be interpreted as meaning a housing which forms ahousing compartment for a product container in which the productcontainer has not yet been inserted.

In some embodiments, the conveying mechanism is mounted, so that it canbe moved, by a mechanism holder, which may be a housing portion. It mayperform a conveying motion by which the product is conveyed out of thereservoir and dispensed. It can be moved relative to the housing or atleast a part of the housing into at least two, and in some embodiments,exactly two, different positions which are pre-defined by stops. One ofthe positions is a triggering position from which the conveying movementis performed directly or after firstly performing another movement. Theother position is a release position, from which the conveying mechanismcan be moved into the triggering position.

In some embodiments, the conveying movement and the movement into thetriggering position are linear movements, and in some embodiments, maytake place along a single translation axis. The movement out of therelease position into the triggering position may be in exactly theopposite direction from the conveying movement. The conveying mechanismis able to move backwards and forwards between the triggering positionand the release position, and, in some embodiments, moves exclusively inthis manner. The movement out of the triggering position may beinitiated by manual pressure on the conveying mechanism and the movementinto the triggering position may be activated by manually appliedtension. To simplify matters, the movement into the triggering positionwill be referred to as the re-setting movement. The fact that theconveying mechanism performs a movement does not mean, in the case ofone preferred multi-part design of the conveying mechanism, that allparts of the conveying mechanism always perform the movement in questionor that they perform a joint movement at all, although a joint movementis preferred in at least certain phases and/or embodiments.

In some embodiments, the dose metering mechanism is mounted, e.g.,connected, to said mechanism holder, so that it is able to perform adose metering movement relative to the conveying mechanism or at least apart of the conveying mechanism, to set or select the product dose to beconveyed by the conveying mechanism. The product dose which can be setis pre-defined by dose positions, into which the dose metering mechanismreleaseably moves or latches during the dose metering movement. Thecorresponding latched engagement may be formed by the housing or/and theconveying mechanism. The dose may be set in readiness when the conveyingmechanism assumes the release position. The pre-defined dose meteringpositions may be only two different dose metering positions, so that twodifferent product doses can be administered at different times of theday, for example. In other embodiments, more than two, e.g., a pluralityof different dose metering positions are provided, to adapt to differentsituations and/or provide the option of enabling an individual dose tobe set for product doses to be administered for a heterogeneous group ofpersons.

In accordance with some embodiments of the present invention, the dosemetering mechanism is coupled to conveying mechanism by a blocking orlock engagement when the conveying mechanism assumes the triggeringposition. The blocking engagement may also exist already during there-setting movement of the conveying mechanism. In the blockingengagement, the dose metering mechanism is locked against dose movementsrelative to the conveying mechanism in the previously set dose position.A forced movement out of the blocked dose position is only possible byapplying an extraordinarily strong force and this results in the devicebeing badly damaged, which then makes it impossible to use the devicefor administering the product any more. The advantage is that the doseis set in the release position and a “subsequent dose” can not then beset in the triggering position. Because it is blocked or locked in thetriggering position, the injection device can be safely manipulated foradministering purposes because the manipulations needed to proceed withthe administering action can not accidentally lead to the set dose beingadjusted. Although in some embodiments the dose metering mechanism isguided tightly in the blocking engagement to prevent movementstransversely to the direction of the re-setting movement, a certainamount of clearance may be provided in principle, as long as there is nopossibility of causing an adjustment to the set dose.

As mentioned above, the triggering position is a stop position. For dosemetering purposes, this stop position is adjustable in and opposite thedirection of the conveying movement and the maximum path length of theconveying movement is therefore also adjustable. The conveying mechanismand the dose metering mechanism respectively serve as a dose settingstop p and the two dose setting stops delimit the re-setting movement ofthe conveying mechanism and thus determine the triggering position. Thismeans that one of the conveying mechanism and dose metering mechanism,in some preferred embodiments, the dose metering mechanism, forms a stopwhich can be varied in terms of its position. An example of anadjustable dose setting stop which differs from that of the presentinvention is disclosed in patent specification WO 97/36625. Based on thereverse kinematics in terms of their paths, i.e. as discrete dosesetting stops, the dose setting stops disclosed therein could also beprovided on the conveying mechanism, in which case it would be enough toprovide a stop cam on the dose metering mechanism which is set in a doseposition by the dose metering movement.

In some preferred embodiments, the dose metering mechanism is blockeddue to the engagement of at least one selection element between tworotation stops. This ensures that, for each of the dose meteringpositions, one of the conveying mechanism and dose metering mechanismforms a selection element and the other forms two co-operating rotationstops which are locked with one another in engagement. As a result ofthe various different dose setting positions, several co-operatingrotation stop pairs and/or several selection elements are provided, ofwhich at least one pair is in the blocked engagement in each of the dosesetting positions. In some preferred embodiments, several pairs are in ablocked engagement. The rotation stops or the selection element may berigidly formed on the conveying mechanism and in particular may beintegral with it. The at least one complementary element formed by thedose metering mechanism may be rigidly formed on the dose meteringmechanism or may be integral with it.

The engagement between the selection element and the rotation stops maybe released when the conveying mechanism is in the release position ormay be provided in the form of a releasable catch engagement, which mayadvantageously also constitute at the same time the releasable catchengagement for the dose selection when the conveying mechanism is in therelease position. In the latter variant, the blocking engagement becomesweaker during the movement into the release position up to of the catchengagement; conversely, the catch engagement prevailing in the releaseposition becomes stronger relative to the blocking engagement during there-setting movement of the conveying mechanism.

In some embodiments, the rotation stops may be provided in the form ofguide grooves or projecting guide webs, which may extend over only asmall part or over virtually the entire path length of the re-settingmovement of the conveying mechanism. If the selection element is rigid,the rotation stops may extend as close as possible to the selectionelement when the conveying mechanism assumes the release position. Inthe release position, if the selection element or the several selectionelements are in a releasable catch engagement with the guide or therotation stops, the rotation stops extend accordingly across a longerdistance.

In some preferred embodiments, the dose metering movement comprises arotating movement of the dose metering mechanism relative to theconveying mechanism about a rotation axis. The dose metering movementmay be a purely rotating movement. It may also be a super-imposedmovement involving a rotating movement and a movement in translation,and, this being the case, along the rotation axis. The conveyingmovement of the conveying mechanism comprises a movement of theconveying mechanism relative to the dose metering mechanism along therotation axis. In some embodiments, the conveying movement may be apurely linear movement along the rotation axis, and, in suchembodiments, it may be that one of the structures, namely the conveyingmechanism or the dose metering mechanism, at least partially surroundsthe other about the rotation axis and the requisite number of rotationstops and/or selection elements are disposed on casing surfaces of theconveying mechanism and the dose metering mechanism lying opposite oneanother. The one of the two structures which at least partiallysurrounds the other, e.g., the dose metering mechanism, is or comprisesa sleeve body and forms the rotation stops.

In some embodiments, the conveying mechanism may be made as a singlepart but also may be made up of several parts. In the case of themulti-part design, it comprises a conveying element which performs theconveying movement and thus acts directly on the product contained inthe reservoir, and a drive mechanism which is coupled to the conveyingelement, causing its conveying movement. The drive mechanism comprisesan output element and a drive element which can be moved relative to oneanother and are coupled to with one another so that a driving movementof the drive element causes an output movement of the output element.The output element may be rigidly connected to the conveying element oris coupled to the conveying element so that the output movement of theoutput element causes the conveying movement. The output element simplydrives the conveying element with it during its output movement. Thedrive element is mounted so that it is able to perform the drivingmovement on the one hand and perform a movement opposite the directionof the driving movement into the triggering position of the conveyingmechanism on the other hand. The drive element and the output elementare coupled to one another so that the drive element drives the outputelement with it during the driving movement, whereas the driving elementperforms the movement in the opposite direction without the outputelement. Drive mechanisms of this type are known from injection pens,for example as disclosed in patent specifications WO 97/36625 and DE 19900 792 C2. Also suitable would be a drive mechanism of the typedescribed in patent specification DE 199 45 397 C2, for example, wherebythe output element is smooth and the drive element has engaging elementswhich press into the smooth external surface of the output element. Themovements of the conveying mechanism and, in the multi-part design, themovements of the elements of the conveying mechanism comprise or arelinear movements along a translation axis of the conveying mechanism.

If, as in some preferred embodiments, the dose metering mechanismconstitutes the rotation stops, its dose setting stop or dose settingstops, is or are disposed at the end of the rotation stops.

In some embodiments, the conveying mechanism is designed for manualactivation. However, it may also have a motorised drive which causes theconveying movement and is triggered when the conveying mechanism is inthe triggering position. In both embodiments, it has an operatingelement, in the one instance for manual activation and causing theconveying movement and in the other instance for triggering themotorised drive. In the case of manual activation, which may bepreferred for applications involving injection devices, the user appliesthe force needed to produce the conveying movement by means of theoperating element.

Advantageously, a path length which the operating element travels duringactivation is larger or longer than a path length of the conveyingmovement which the conveying mechanism travels in order to dispensecompletely the set product dose. This larger path length is ofparticular advantage if the path length of the conveying movementcorresponding to the set product dose is very short, for example one ora few millimeters or even less than one millimeter. If the movement ofthe operating element likewise extended over such a short path length,misinterpretations could arise and the user might think that he had notadministered the product dose or had not completely administered it.

The longer activation path of the operating element compared with theconveying movement can be achieved on the basis of a gear mechanismwhereby the movement of the operating element is constantly andcontinuously reduced in the conveying direction by means of a reducinggear. Not least for reasons of simplicity, however, the activation pathof the operating element comprises a free movement of the operatingelement without any conveying movement and a joint movement of theoperating element with the conveying movement 1:1.

In another embodiment, the drive and dose metering module has a dosemetering element which can be moved relative to a drive member into oneof several dose setting positions to set or select the product dose(i.e., the amount to be delivered), wherein one of the drive member anddose metering element forms several dose stops at different axialheights and rotation stops assigned to the dose setting stops, and theother of the drive element and dose metering element forms at least oneselection element. The drive member can be moved in translation relativeto the dose metering element as far as a triggering position in whichthe at least one selection element is in abutment with one of the dosesetting stops. In the triggering position, the at least one selectionelement with the rotation stops locks the rotation of the dose meteringelement in both directions.

In some embodiments, the dose metering element corresponds to a dosesetting mechanism. The dose metering element may specifically besleeve-shaped and can be rotated relative to the drive element in orderto set the product dose. Depending on the rotation angular position,several dose setting positions can be set as a result. The dose meteringelement may have several dose setting stops, which may be distributed onthe external peripheral surface and, if the dose metering element issleeve-shaped, on the internal circumferential surface of the sleeve.The dose setting stops sit at different positions in the axial directionso that the drive member can be moved along paths of differing lengthsin the axial direction, depending on the set dose. In some preferredembodiments, the dose metering element can be rotated relative to theoutput element into one of several dose setting positions in order toset the product dose, in which case the drive element is mechanicallycoupled to the output element and can be moved in translation relativeto the output element. The product dose advantageously depends on thedifferent axial heights of the several dose setting stops. The dosesetting stops may be distributed around the periphery.

The dose setting stops may respectively be provided in the form of anend face of a groove, in which case the groove extends axially from afront face of the component containing the dose setting stops into thecomponent. The groove is advantageously open across a half side in itslongitudinal direction so that the selection element is able to slipinto the groove or be moved into it. The grooves may be provided on aninner circumferential surface of a sleeve or on an external face of anelement locating in a sleeve. In one preferred embodiment, the groovesextend in the axial direction and have a pocket-type shape so that theselection element is only able to engage in the groove from the internalface. The depth of the pocket-shaped grooves is shorter than the wallthickness of the sleeve. In principle, the grooves could be of acontinuous design so that their depth corresponds to the wall thicknessof the sleeve. Starting from the end face or at an axial distance fromthe end face of the component containing the dose setting stops, thegrooves may extend as far as the dose setting stops.

In some embodiments, webs serving as rotation stops remain between thegrooves which are advantageously disposed around the circumference. Inparticular, the rotation stops are formed by the sides of the groove orgrooves.

In one preferred embodiment, one of the drive element and dose meteringelement has dose setting stops axially directed towards the other in astepped arrangement. Here too, the sides of the grooves may form therotation stops. A rotation stop should be disposed between each stage ofthe stepped arrangement. In principle, it is also possible to dispensewith a web between some stages. The groove may also form two or moredose setting stops at its end face. The dose setting stops disposed in astepped arrangement in the circumferential direction may be of aconstantly rising and constantly descending design but this is notintended to imply that they are restricted to these options. In onepreferred embodiment, the dose setting stops are formed by the dosesetting element and the at least one selection element is formed by theoutput element. The at least one selection element may be a cam or a webextending in the axial direction, which preferably projects out from acasing surface of the drive element or the dose setting element. Threeselection elements may be provided.

In some embodiments, a mechanism holder may be provided, with which thedose setting element is mechanically coupled, in which case the dosesetting element may be rotated relative to the mechanism holder. Thedrive element may also be mechanically coupled to the mechanism holder,in which case the drive element can be moved in translation relative tothe mechanism holder.

In another embodiment, the drive and dose setting module has a dosesetting element and a mechanism holder, relative to which the dosesetting element can be rotated, and one of the mechanism holder and dosesetting element has at least one locking element and the other of themechanism holder and dose setting element has at least one lockcomplementary element, in which the lock element can engage and lock toprevent rotation of the dose setting element relative to the mechanismholder. The lock element may be resilient in the radial direction. Theresilient arrangement may be achieved by means of a spring element. Thespring element may be a spring for example. The spring may be formed bya portion of the component incorporating the lock element. In somepreferred embodiments, the at least one lock element, the at least onespring element co-operating respectively with the at least one lockelement and one of the mechanism holder and dose setting element areintegral, and in some embodiments, the at least one lock element isformed on the dose setting element, in which case the at least one lockcomplementary element is formed on the mechanism holder.

The number of lock complementary elements may be greater than or thesame as the number of lock elements. In some embodiments, the number oflock complementary elements corresponds to the number or a multiple ofthe number of dose setting stops. The number of lock complementaryelements may also be only a fraction of the number of dose settingstops. In principle, the lock complementary elements are distributed inthe circumferential direction. It may also be of advantage if the lockcomplementary elements are disposed in certain portions around thecircumference. One of the dose setting element and the drive elementadvantageously has several dose setting stops distributed about thecircumference, in which case several lock complementary elements areprovided with the same angular pitch as the dose setting stops. The atleast one locking element should be disposed in a positionalrelationship with the dose setting stops and/or the grooves co-operatingwith them such that at least one locking element is able to sliprespectively into a lock complementary element when the at least oneselection element is moved into a groove of the component containing thedose setting stops. The angular pitch of the dose setting stops andhence also that of the lock complementary elements may be identical.However, a different angular pitch would also be conceivable.

In some preferred embodiments, a blocking element may hold the lockelement in a locking engagement with the lock complementary element.This locks the rotation of the dose setting element relative to themechanism holder. In one embodiment, the lock element may be disengagedfrom the lock complementary elements and engaged with the lockcomplementary element by the blocking element so that the rotation ofthe dose setting element relative to the mechanism holder is locked. Inanother embodiment, the lock element is engaged with the lockcomplementary element without the blocking element holding the lockelement in the locking engagement. When the dose setting elementrotates, the lock element is pushed out of the lock complementaryelement and as the rotation continues, latches in the next or adjacentlock complementary element. This is continued until the desired dose hasbeen set by rotating the dose setting element. Since the lock element isblocked by the blocking element, the lock element can no longer slip outof the lock complementary element, as a result of which the rotation ofthe dose setting element relative to the mechanism holder is locked. Theblocking element is moved in translation into a blocking engagement withthe lock element. It would also be conceivable for the blockingengagement to be obtained by a rotating movement or a combination of arotating movement and a movement in translation.

In some embodiments, a blocking element is formed on or by an operatingelement. The blocking element may be provided in the form of a radiallyprojecting circumferential collar or a shoulder of a sleeve, and shouldrelease the lock element at least in a release position. The lockelement or elements is or are blocked as long as the blocking element islying opposite them. The blocking element may extend in the longitudinaldirection across a length which is large enough to prevent rotationacross a long extraction path of the operating element. It would also beconceivable for the blocking element to be only so long that it preventsrotation at the smallest possible dose or the first smallest possibledoses. The blocking element could block the lock element if, when thereare one or more selection elements, not all the selection elements areengaged with the grooves. An axial length of the blocking element may beshorter than the path by which the blocking element can be moved intranslation for a maximum set dose minus twice the axial length of thelock element. This being the case, the blocking element would releasethe lock element at a high dose but at the latest by the maximumpossible dose. The blocking element could also then release the lockelement if, when there are one or more selection elements, all theselection elements engage with a groove. Rotation would then be blockedby means of all the selection elements moved into the groove or into thegrooves. This would enable the structural length of the drive and dosemetering module to be reduced.

In another embodiment, the at least one selection element may be of amulti-part design. It would be conceivable to provide two or moreselection part-elements axially one after the other. At least one of theselection part-elements may be moved into abutment with a dose settingstop in order to select the dose. Another of the selection part-elementsmay be used as an anti-rotation lock.

In another embodiment, at least one groove constituting the rotationstops is spaced apart from the dose setting stop. In principle, thegroove or the webs forming the sides of the groove could be interruptedin their axial extension. The webs may act as an axial guide. Aselection part-element forms an anti-rotation lock, for example inconjunction with the sides of the groove, in which case the otherselection part-element is moved into an axial abutment with the dosesetting stop to select the dose.

In some embodiments, the drive and dose setting module may be fittedwith the different mechanisms described above, which prevent a productdose from being metered outside the release position. Features of thepresent invention may be used in any combination with one another.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an embodiment of an injection device,

FIG. 2 is a perspective view of an embodiment of a dose meteringmechanism in accordance with the present invention,

FIG. 3 is a perspective view of an embodiment of a drive element inaccordance with the present invention,

FIGS. 4-9 illustrate how the dose metering mechanism and drive elementco-operate in accordance with the present invention,

FIG. 10 is a perspective view of an embodiment of a dose meteringmechanism,

FIG. 11 shows an embodiment of a lock element in accordance with thepresent invention, and

FIGS. 12-15 illustrate an embodiment of a drive and dose metering modulein accordance with the present invention.

DETAILED DESCRIPTION

FIG. 1 shows an embodiment of an injection device in the form of aninjection pen in accordance with the present invention. The injectiondevice has a two-part housing 20 comprising a distal (or front orforward) housing portion and a proximal (or back or rear) housingportion, which are fixedly connected to one another, for example screwedtogether. A housing compartment of the housing 20 forming its distalhousing portion contains a reservoir 21. Attached to a distal outlet ofthe reservoir 21 is an injection needle N. The longitudinal axis of theinjection needle N forms a central longitudinal axis R of the injectiondevice. A plunger 22 closes off the proximal end of the reservoir 21.The plunger 22 is able to perform a conveying movement along the axis Ronto the outlet of the reservoir 21 in order to force product out of thereservoir 21. The reservoir 21 is a commercially available ampoule,filled with the product to be administered, for example insulin.

The plunger 22 is the conveying element of a conveying mechanism actingdirectly on the product, which, in addition to the plunger 22, also hasan output element 2, a drive element 3 and an operating element 10. Dueto the fact that the conveying element is provided in the form of aplunger 22, the output element 2 acting directly on the plunger 22 is aplunger rod and will therefore be referred to as such herein. When theconveying mechanism is activated, the plunger rod 2 also performs theconveying movement and thus forces the plunger 22 in the distaldirection. The plunger rod 2 is provided in the form of a toothed rackwith several rows of teeth extending in the direction of the axis Rwhich are respectively offset from one another along the axis R by lessthan one tooth pitch in order to make the dose selection finer. Thedrive element 3 can be moved along the axis R in the distal and proximaldirection. The drive element 3 and the plunger rod 2 are coupled to oneanother so that the drive element 3 drives the plunger rod 2 with it asit moves in the distal direction but performs the movement in theproximal direction without the plunger rod 2. In the embodimentillustrated as an example, the coupling is brought about by theengagement of drivers in the rows of teeth of the plunger rod 2. Theengagement is such that a movement of the plunger rod 2 in the distaldirection relative to the drive element 3 is prevented and a movement ofthe drive element 3 in the proximal direction relative to the plungerrod 2 is permitted. To prevent the plunger rod 2 from being drivenduring the movement in the proximal direction, the proximal portion ofthe housing 20 forms a retaining mechanism 23 which, like the driver ofthe drive element 3, engages in at least one, but in the embodimentillustrated as an example, two rows of teeth of the plunger rod 2 sothat the plunger rod 2 can be moved relative to the housing 20 in thedistal direction but not in the proximal direction. This is achieved dueto the fact that the teeth of the rows of teeth are of a saw-toothshape. The proximal portion of the housing 20 provides a mount for theplunger rod 2 as well as the drive element 3 so that these elements ofthe conveying mechanism are not able to perform any rotating movementsabout the axis R relative to the housing 20. Since the proximal portionof the housing 20 at least partially incorporates the dose metering andadministering mechanism, it may also be termed a mechanism holder 1.

For every injection, the injection device enables the free selection ofa product dose which can be administered. To select and/or set theproduct dose, a dose metering element 4 is provided, which is able toperform a dose metering movement relative to the conveying mechanism, inparticular relative to its drive element 3. The proximal portion of thehousing 20 also accommodates the dose metering element in an appropriatemanner for performing the dose metering movement. In the embodimentillustrated as an example, in which the dose metering movement is arotating movement about the axis R, the mechanism holder 1 of thehousing 20 provides a mount for the dose metering mechanism 4 enablingit to rotate about the axis R. The axis R therefore forms thetranslation axis for the conveying mechanism and the rotation axis forthe dose metering element 4. When performing the dose metering movement,the dose metering element 4 can be moved between discrete pre-defineddose setting positions in the form of catch positions. To this end, itsits in a releasable catch engagement with the proximal portion of thehousing 20 in each of the dose setting positions. As regards the dosemetering element 4, it should also be pointed out that in the embodimentillustrated as an example, it is provided in the form of a sleeve bodyand surrounds the drive element 3 as well as the operating element 10.The drive element 3 and the operating element 10 are likewise eachprovided in the form of a sleeve body, whereby the operating element 10surrounds a proximal end portion of the drive element 3 and projects outof the dose metering element 4 in the proximal direction to permitmanual activation of the conveying mechanism. The drive element 3,finally, surrounds the plunger rod 2.

To set the product dose, the drive element 3 constitutes a selectionelement 6 and the dose metering element 4 a dose stop 8 lying oppositethe selection element 6 in the proximal direction. The dose settingelement 4 forms its dose stop 8 by means of a distal end face, whichrespectively bounds two rotation stops 5 extending from the distal endface 7 of the dose metering element 4. The drive element 3 forms itsselection element 6 by means of a cam projecting radially outwards, theshape of which is adapted to the width of a groove 9 formed by tworotation stops or to the width of the dose stop 8, respectively.

In the state illustrated in FIG. 1, the conveying mechanism has assumeda position in the housing 20 closest to the distal end. In this state,the product dose is set by means of the dose metering element 4, wherebya dose setting stop 8 corresponding to the desired product dose is movedalong the axis R into the dose metering position lying opposite theselection element 6. The distance left between the dose setting stop 8and selection element 6 and 27 as measured along the axis R in therelevant dose metering position corresponds to the path length, i.e. theconveying stroke, which the drive element 3 can cover together with theplunger rod 2 and the plunger 22 during the injection. After setting theproduct dose, the drive element 3 and, due to the engagement, theplunger rod 2 with it are pulled in the proximal direction by pulling onthe operating element 10 until the selection element 6 makes contactwith the dose setting stop 8. The conveying mechanism then assumes atriggering position, from which a pressing force acting on the operatingelement 10 can be applied in the distal direction for the injection. Itis clear that prior to the injection, the housing cap illustrated inFIG. 1 as well as the needle guard cap must be removed.

The proximal portion of the housing 20, the parts of the conveyingmechanism mounted by this portion and the dose metering element 4fixedly connected to the housing portion except for the dose meteringmovement constitute a drive and dose metering module, may be of the typeknown from patent specification DE 199 00 792 C2. This module may bereplaced by a drive and dose metering module of the type provided inaccordance with the present invention.

FIG. 2 illustrates an exemplary embodiment of a drive and dose meteringmodule in accordance with the present invention. Parts which fulfill thesame functions as those of the drive and dose metering module shown inFIG. 1 are denoted by the same reference numbers.

The drive and dose metering module of the present invention has a dosemetering lock in the form of several rotation stops 5, which prevent theset product dose from being adjusted when the conveying mechanism is inthe triggering position. The dose metering lock is based on anengagement between the conveying mechanism and the dose metering element4, which blocks dose metering movements of the dose metering element 4relative to the conveying mechanism when the conveying mechanism is inthe triggering position and will therefore be referred to as a blocking(or locking) engagement.

FIG. 2 illustrates a dose setting mechanism 4 in the form of a dosemetering element 4. The dose metering element 4 is of a sleeve-shapeddesign. The external face of the sleeve has several shoulders, which,amongst other things, serve as a gripping surface or element by which acoupling with a mechanism holder 1 is possible. Disposed on the internalface of the sleeve are dose setting stops 8. The dose setting stops 8are disposed at different axial heights. In particular, the dose settingstops 8 are distributed around the circumference in a steppedarrangement. In the example illustrated, the step descends constantlyand rises constantly. The angle between one dose setting stop 8 and thenext dose setting stop 8 or any other dose setting stop 8 is shown by Wdenoting the angular pitch. The angular pitch W and/or the number ofdose setting stops 8 should correspond to that of the lock complementaryelements 16 in the mechanism holder 1, for example.

Between the step stages or the dose setting stops, webs extend in thelongitudinal direction, which form rotation stops by means of theirsides. The combination of two webs and at least one dose setting stop 8may also be described as a groove 9, in which case the groove 9 is openat one half face and the sides of the groove 9 form the rotation stops5. The webs contained by the rotation stops 5 project respectively froma dose setting stop 8 in the longitudinal direction R, the height andwidth of the web being shorter than the height and width of theco-operating dose setting stop. Using this design of web incorporatingthe dose setting stop, an end face 19 (FIG. 3) of a selection element 6may be made in a stronger and more wear-resistant design. The distancebetween two sides 5 forming a groove 9 is bigger than the width B of aselection element 6.

The end faces of a web, formed on the open end face of a groove 9, areaxially offset into the dose metering element 4 from an end face 7 ofthe dose metering element 4.

FIGS. 2, 10 and 11 specifically illustrate two locking elements 15,lying diametrically opposite one another, which are disposed on the dosemetering element 4 so that they are resilient in the radial direction.The locking element 15 is disposed in a window-type orifice of the dosemetering element 4. The dose metering element 4 forms two springelements 18, each of which is connected to the lock element 15. Due tothe structural design of the spring elements 18, the lock element 15 isable to spring in the radial direction. In the example illustrated, thelock elements 15, spring elements 18 and dose metering element 4 aremade in a single piece. The lock element 15 is rounded at its endpointing radially outwards, to enable it to latch more easily out of andinto the next or adjacent lock complementary element 16. Due to the dosesetting movement of the dose metering element 4, the lock element 15 isforced out of the respective lock complementary element 16 due to itsadvantageous design and latches in the next lock complementary element16 as a result of the spring action of the spring elements 18.

FIGS. 3 and 9 illustrate a drive element 3 in accordance with thepresent invention. At its distal end, the drive element 3 has severalretaining mechanisms 11 for an output element 2. In particular, at leastone selection element 6 is disposed on the outer peripheral surface ofthe drive element 3. As may be seen from FIG. 3, it is of particularadvantage to provide three selection elements 6 on the drive element.The shape of the end faces 19 of the selection elements 6 more or lessmatches the mirror image of the dose setting stops 8. In the exampleillustrated, the selection elements 6 are webs extending in thelongitudinal direction R, the width B of which is adapted so that theycan be moved into the grooves 9 of the dose metering element 4.

FIG. 4 illustrates the drive element 3 and the dose metering element 4in a release position. The dose metering element 4 can be rotatedrelative to the drive element 3. None of the three selection elements 6is engaging in a groove 9 of the dose metering element 4.

FIG. 5 illustrates the dose metering element 4 and the drive element 3in a triggering position for at least a smallest possible product dose.The end faces 19 of the selection elements 6 are also disposed atdifferent axial heights matching the dose setting stops 8. Consequently,only one end face 19 is in abutment with a dose setting stop 8. Thisexample does not enable rotating movement to be locked because theselection element 6 does not engage in a groove 9. To prevent the dosemetering element 4 from nonetheless twisting against the drive element3, it is advantageous to additionally secure the dose metering element 4against rotation using a lock element 15.

FIG. 6 illustrates the dose metering element 4 and the drive element 3in a triggering position, in which an end face 19 of two selectionelements 6 respectively sits in abutment with a respective dose settingstop 8. In addition, one selection element 6 is engaged in a groove 9 bymeans of its sides 24, as a result of which the dose metering element 4is prevented from rotating against the drive element 3 in bothdirections. The overlap of the sides 24 of the selection element 6 withthe rotation stops 5 is only very slight, however, so that a slightlyhigher torque on the dose metering element 4 could possibly lead totwisting of the dose metering element 4 against the drive element 3. Thedose metering element 4 is therefore additionally prevented fromrotating by means of one, preferably two, lock elements 15.

FIG. 7 illustrates the end faces 19 of the selection elements 6respectively in abutment with a dose setting stop 8. Two of the threeselection elements 6 have latched into the grooves 9 and form ananti-rotation lock. The overlap of the sides 24 with the rotation stops5 is somewhat bigger than was the case with FIG. 6. It would also be ofpractical advantage to provide additional anti-rotation locking by meansof lock elements 15.

In FIG. 8, the drive element 3 is in a triggering position, in whichcase all three selection elements 6 have latched into a groove 9,thereby providing an anti-rotation lock in both directions. Inprinciple, the tightness of the locking action of the dose meteringelement 4 against the drive element 3 also increases with the setproduct dose. Consequently, in the case of a higher product dose, theadditional anti-rotation lock provided by the lock elements 15 can bedispensed with. The lock elements 15 prevent the dose metering element 4from rotating against the drive element 3 only as long as all engagingelements locate respectively in a groove for the first time.

FIGS. 12-15 illustrate the drive and dose metering module used in oneembodiment of the present invention. It comprises a mechanism holder 1,which might also be termed a proximal housing portion 1. At its frontend, the mechanism holder 1 forms retaining mechanisms 23 which areattached to the distal end of the mechanism holder 1 in an oscillatingmanner so that they are able to bend elastically about their anchoringpoint. The retaining mechanism 23 engages in an output element 2. Theoutput element is a forward-drive rod or a rod with teeth of a saw-toothdesign. The retaining mechanism 23 and plunger rod 2 engage with oneanother due to their saw-tooth contours. The oblique surfaces of theteeth point in the distal direction, in other words, in the direction inwhich the plunger of the reservoir will subsequently be moved.

The mechanism holder 1 partially encloses a dose metering element 4 andsimultaneously provides a mount for it. The dose metering element 4 ismounted in the mechanism holder 1 so that it is only able to move inrotation. This is achieved due to the fact that catch lugs are providedon the mechanism holder 1, which locate in a radial groove extendingaround the dose metering element 4, thereby preventing axial movement ofthe dose metering element 4 relative to the mechanism holder 1. The dosemetering element 4 may have several shoulder-type peripheral surfaces.Disposed at the proximal end of the dose metering element 4 is a portionwhich forms a surface enabling a user to rotate the dose meteringelement 4 relative to the mechanism holder 1. This surface may bereferred to as a gripping surface 14. Formed on another portion of thedose metering element 4 is a scale drum 12, on the peripheral face ofwhich is a scale from which a user of the device can take a reading ofthe product dose he has set. To this end, the mechanism holder 1 has awindow, enabling one of the scale values to be read from the scale 13.

The dose metering element 4 may correspond to the dose metering elements4 already described. The dose setting stops 8 are at different axialdistances from the end face 7. These different distances of the dosesetting stops 8 from the end face 7 each correspond to a product dose.The number of grooves 9 may determine the number of individual elementsof the scale 13. Preferably, the number and pitch of the elements of thescale 13 are the same as that of the stepped arrangement of the dosesetting stops 8.

The dose metering element 4 provides a mount for the drive element 3. Arelative rotating movement is possible between the drive element 3 anddose metering element 4. The drive element 3 is also mounted by means ofthe mechanism holder 1. The drive element 3 is able to performtranslating movements only relative to the mechanism holder 1. This isdue to mutually engaging elements formed between the mechanism holder 1and the drive element 3. In some preferred embodiments, the mechanismholder 1 is provided with a cam or some other projecting structure,which engages in a groove in the mechanism holder 1. The groove isoriented in the axial direction. This prevents the rotating movement ofthe drive element 3 relative to the mechanism holder 1 but permits theaxial movement.

Disposed at the distal end of the drive element 3 are retainingmechanisms 11 which, like the toothed rack 2, have teeth of a saw-toothdesign and engage in the plunger rod 2. The retaining elements 11 areformed as wings and are attached to the distal end face of the driveelement 3. The retaining mechanisms 11 are able to move elasticallybackwards and forwards about their anchoring point on the drive element3. The retaining mechanisms 11 of the drive element 3 correspond tothose of the retaining mechanisms 23 of the mechanism holder 1.

At its proximal end, the drive element 3 has a connecting element, whichenables a connection with an operating element 10. The operating element10 and drive element 3 are connected to one another in such a way thatwhen the operating element 10 is pulled out of the dose metering element4, the drive element 3 is driven with it.

The drive element 3 may correspond to the drive elements 3 alreadydescribed. The dimensions of the selection element 6 are such that theselection element 6 can be moved into the grooves 9.

As described above, the lock elements 15 are disposed so that theyspring in the radial direction and may be an integral part of the dosemetering element 4. Several lock complementary elements 16 are uniformlydistributed around the mechanism holder 1, e.g., in the circumferentialdirection. Since a single lock element 15 would be sufficient to providean anti-rotation lock in principle, the way in which the one lockelement operates will be described, although the explanation alsoapplies if several lock elements 15 are provided. In the releaseposition, the dose metering element 4 is able to rotate against themechanism holder 1. In the embodiments illustrated in FIGS. 12-15, thelock element 15 is in the release position, in a latched engagement witha lock complementary element 16. The lock complementary elements arecatch grooves, for example, lying opposite the lock element 15. Byrotating the dose metering element 4, the lock element 15 is forcedradially inwards and out of the respective lock complementary element 16due to the rotating movement. The lock complementary element 16 latchesinto the next lock complementary element 15. A blocking element 17 isdesigned so that it is able to block the inwardly directed movement ofthe lock element 15. The blocking element 17 is a collar on theoperating element 10 pointing radially outwards. In order to block thelatching movement of the lock element 15, the operating element 10 ismoved in the proximal direction so that the blocking element 17 is movedin a region within the lock element 15 and thus blocks the latchingmovement of the lock element 15. As an alternative, the lock element 15could also be disengaged from out of the lock complementary element 16in the release position. Due to the blocking element 17, the lockelement 15 could be engaged with one of the lock complementary elements16. Due to the movement of the operating element 10 in the proximaldirection, the blocking element 17 would push the lock element 15radially outwards so that the lock element 15 in conjunction with thelock complementary element 16 would ensure that any rotation wasprevented in both directions.

To set a dose, the grooves 9 are turned by rotating the dose meteringsleeve 4 relative to the drive element 3 until the desired grooves 9 lieopposite the selection elements 6. The dose is determined on the basisof the axial distance between the dose setting stops 8 and the selectionelements 6. The product dose is set by means of the different depths ofthe grooves 9 and due to the axial height of the dose setting stops 8.When the desired grooves 9 lie opposite the selection elements 6, theoperating element 10 is pulled out relative to the dose metering sleeve4 so that the selection elements 6 move into the desired grooves 9 asfar as the dose setting stops 8. The rotation stops 5 prevent anyadjustment being made to the dose by means of the dose metering sleeve4. By extracting the operating element 10 and the drive element 3coupled to it, the retaining mechanisms 11 perform an outward swingingmovement because their surfaces extending at an angle to thelongitudinal axis slide on one another. In the release position, theretaining mechanisms latch into the plunger rod 2. The plunger rod 2 isnot pulled back by the backward movement of the operating element 10because the retaining mechanisms 23 prevent the plunger rod 2 from beingpulled back.

To administer the product, the operating element 10 is pushed in thedistal direction so that the drive element 3 coupled to it also movesthe retaining mechanisms 11 in the distal direction. Due to the teeth ofthe retaining mechanism 11, the output element 2 is also driven along inthe distal direction. The retaining mechanisms 23 of the mechanismholder 1 therefore snap out and only then snap back in again once themovement of the plunger rod 2 has ended, due to the oblique surfaces ofthe teeth.

FIG. 12 illustrates the drive and dose metering module in a releaseposition prior to administering. The blocking element 17 is not in theregion of the lock element 15 and the lock element 15 is therefore ableto perform inwardly directed latching movements. The dose is set byrotating the dose metering element 4.

FIG. 13 illustrates the drive and dose metering module as the operatingelement 10 is being pulled back in the proximal direction. The blockingelement 17 is moved into the region of the lock element 15 and thereforeblocks the inwardly directed latching movements. A dose can now nolonger be set because the dose metering element 4 is locked in bothdirections of rotation.

FIG. 14 illustrates the drive and dose metering module in a triggeringposition, in which the lock element 15 is blocked. Furthermore, becausethe operating element 10 has been pulled back, the drive element 3 hasbeen driven along by the operating element 10. The drive and dosemetering module is now ready for administering the set product dose.

FIG. 15 illustrates the drive and dose metering module in a releaseposition after administering. The output element 2 has been moved in thedistal direction depending on the set dose. The lock element 15 has beenreleased by the blocking element 17 again so that a new dose can be setwith the dose metering element 4, thereby making it possible toadminister another product dose subsequently.

Embodiments of the present invention, including preferred embodiments,have been presented for the purpose of illustration and description.They are not intended to be exhaustive or to limit the invention to theprecise forms and steps disclosed. Obvious modifications or variationsare possible in light of the above teachings. The embodiments werechosen and described to provide the best illustration of the principlesof the invention and the practical application thereof, and to enableone of ordinary skill in the art to utilize the invention in variousembodiments and with various modifications as are suited to theparticular use contemplated. All such modifications and variations arewithin the scope of the invention as determined by the appended claimswhen interpreted in accordance with the breadth they are fairly,legally, and equitably entitled.

1. A drive and dose metering module for an injection device, comprising:a) a dose metering element moveable relative to a drive element into oneof several dose setting positions to set the product dose, b) whereinone of the drive element and dose metering element forms several dosesetting stops at different axial heights and rotation stops assigned tothe dose setting stops, c) and the other of the drive element and dosemetering element forms at least one selection element, d) and whereinthe drive element can be moved in translation relative to the dosemetering element as far as a triggering position in which the at leastone selection element is in abutment with one of the dose setting stops,and e) in the triggering position, the at least one selection elementlocks, by the rotation stops, the rotation of the dose metering elementin both directions of rotation.
 2. The drive and dose metering module asclaimed in claim 1, wherein the dose metering element can be rotatedrelative to an output element into one of several dose setting positionsto set the product dose, and the drive element is mechanically coupledto the output element and can be moved in translation relative to theoutput element.
 3. The drive and dose metering module as claimed inclaim 1, wherein the product dose depends on the different axial heightsof the several dose setting stops.
 4. The drive and dose metering moduleas claimed in claim 1, wherein the dose setting stops are respectivelyprovided in the form of an end face of a groove extending axially froman end face of the component containing the dose setting stops.
 5. Thedrive and dose metering module as claimed in claim 4, wherein therotation stops are the sides of the groove.
 6. The drive and dosemetering module as claimed in claim 5, wherein, on one of the driveelement and the dose metering element the dose setting stops aredisposed in a stepped arrangement pointing axially towards the other andthe sides of the groove form the rotation stops.
 7. The drive and dosemetering module as claimed in claim 1, wherein the dose setting stopsare formed by the dose metering element and the at least one selectionelement is formed by the output element.
 8. The drive and dose meteringmodule as claimed in claim 1, wherein the at least one selection elementis a cam or a web extending in the axial direction which projects from acasing surface of the drive element or the dose metering element.
 9. Thedrive and dose metering module as claimed in claim 1, wherein the dosemetering element is mechanically coupled to a mechanism holder, whereinthe dose metering element can be rotated relative to the mechanismholder.
 10. The drive and dose metering module as claimed in claim 1,wherein the drive element is mechanically coupled to a mechanism holder,wherein the drive element can be moved in translation relative to themechanism holder.
 11. The drive and dose metering module as claimed inclaim 1, further comprising a conveying mechanism having a manuallyoperable operating element, activation of which causes the conveyingmovement, and a path length (H_(F)+H_(L)) of a movement which can beperformed on activation of the operating element is longer than the pathlength (H_(F)) of the conveying movement corresponding to completedispensing of the set product dose.
 12. The drive and dose meteringmodule as claimed in claim 11, wherein the conveying mechanism has atleast one conveying element which is disposed in a reservoir andperforms the conveying movement, and in that the operating element iscoupled to the conveying element so that it slaves the conveying elementacross a part (H_(F)) of the path length (H_(F)+H_(L)) of its movementand travels the other part (H_(L)) of the path length of its movement(H_(F)+H_(L)) without the conveying element.
 13. An injection devicecomprising a drive and dosing module, wherein the module comprises adosing member which can be moved into one of several dosing positions inrelation to a drive member to set a dose, wherein one of the dosing ordrive members forms several dosing stops at axially different heightsand rotational stops that are associated with the dosing stops and theother member forms at least one selection element, and wherein the drivemember can be moved in relation to the dosing member until it reaches atrigger position in which the at least one selection element attains oneof the dosing stops and, in said trigger position, the selection elementand the rotational stops combine to lock the rotation of the dosingmember in both directions.
 14. An injection device for injecting asettable product dose, comprising a drive and dose metering modulecomprising a dose metering element moveable relative to a drive elementinto one of several dose setting positions to set the product dose,wherein one of the drive element and dose metering element forms severaldose setting stops at different axial heights and rotation stopsassigned to the dose setting stops and the other of the drive elementand dose metering element forms at least one selection element, andwherein the drive element can be moved in translation relative to thedose metering element as far as a triggering position in which the atleast one selection element is in abutment with one of the dose settingstops, and in the triggering position, the at least one selectionelement locks, by the rotation stops, the rotation of the dose meteringelement in both directions of rotation.